Expertise

Biography

Ian Pearse is a research ecologist at the Fort Collins Science Center. Ian received a Ph.D. in Entomology from U.C. Davis in 2011. He has conducted research on plant-insect interactions and community ecology, focusing on ways to predict new interactions between introduced species such as plants and herbivorous insects. As part of the invasive species branch, Ian is applying that work to anticipate the impacts of destructive plant and insect invasions.

Invasive, non-native species can have tremendous impacts on biotic communities, where they reduce the abundance and diversity of local species. However, it remains unclear whether impacts of non-native species arise from their high abundance or whether each non-native individual has a disproportionate impact – i.e., a higher per-capita effect – on...

The seasonal assembly of arthropod communities is shaped by biotic and abiotic aspects of the habitat that limit the appearance or activity phenology of potential community members. In addition, previous interactions within the community, such as herbivore-induced plant defensive responses, aggregation, and predator avoidance likely affect the...

The impacts of invasive species generally increase with their abundance, but the form of invader abundance–impact relationships remain poorly described. We highlight the utility of abundance–impact curves for three questions. First, abundance–impact relationships can clarify whether prevention and management should focus on the species likely to...

Many plants employ indirect defenses against herbivores; often plants provide a shelter or nutritional resource to predators, increasing predator abundance, and lessening herbivory to the plant. Often, predators on the same plant represent different life stages and different species. In these situations intraguild predation (IGP) may occur and may...

Defensive variability of crops and natural systems can alter herbivore communities and reduce herbivory. However, it is still unknown how defense variability translates into herbivore suppression. Nonlinear averaging and constraints in physiological tracking (also more generally called time-dependent effects) are the two mechanisms by which...

Declines in monarch butterfly populations have prompted investigation into the sensitivity of their milkweed host plants to land-use change. Documented declines in milkweed abundance in croplands have spurred efforts to promote milkweeds in other habitats. Nevertheless, our current understanding of milkweed populations is poor. We used a long-term...

Pearse, I.S. 2012. The role of leaf defensive traits in oaks on the preference and performance of a polyphagous herbivore, Orgyia vetusta. Ecological Entomology 36(5): 635-642. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2311.2011.01308.x/full

Altermatt, F., Pearse, I.S. 2011. Similarity and specialization of the larval versus adult diets of European butterflies and moths. The American Naturalist 178(3): 372-378. http://www.jstor.org/stable/10.1086/661248?seq=1#page_scan_tab_contents

Pearse, I.S. 2010. Bird rookeries have different effects on different feeding guilds of herbivores and alter the feeding behavior of a common caterpillar. Arthropod Plant Interactions 4: 189-195. http://link.springer.com/article/10.1007/s11829-010-9098-z

Pearse, I.S. and A.L. Hipp. 2009. Phylogenetic and trait similarity to a native species predict herbivory on non-native oaks. Proceedings of the National Academy of Sciences of the United States of America 106(43): 18097-18102. (Cover article)
http://www.pnas.org/content/106/43/18097.short